- Animal behavioral studies have commonly regarded the entire group of animals subjected to the study conditions as homogeneous, disregarding individual differences in response patterns. The following discussion will focus on a method of analyzing data that aims to model clinical diagnostic criteria applied to individual patterns of response using data from behavioral measures, and employing cut-off scores to distinguish between extremes of response versus non-response and the sizeable proportion of study subjects in-between them. This protocol unit will present the concept of the model and its background, provide detailed protocols for each of its components, and present a selection of studies employing and examining the model, alongside the underlying translational rationale of each. Curr. Protoc. Neurosci. 64:9.45.1-9.45.18. © 2013 by John Wiley & Sons, Inc.